// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

//! Sanity check for environment before attempting to run cmake build
//! shamelessly adapted from:
//! https://raw.githubusercontent.
//! com/rust-lang/rust/master/src/bootstrap/sanity.rs
//! more of this will be adapted later

use std::collections::HashMap;
use std::env;
use std::ffi::{OsString, OsStr};
// use std::fs;
// use std::process::Command;
use std::path::PathBuf;

// use build_helper::output;

// use Build;

pub struct Finder {
	cache: HashMap<OsString, Option<PathBuf>>,
	path: OsString,
}

impl Finder {
	pub fn new() -> Self {
		Self {
			cache: HashMap::new(),
			path: env::var_os("PATH").unwrap_or_default(),
		}
	}

	pub fn maybe_have<S: AsRef<OsStr>>(&mut self, cmd: S) -> Option<PathBuf> {
		let cmd: OsString = cmd.as_ref().into();
		let path = self.path.clone();
		self.cache
			.entry(cmd.clone())
			.or_insert_with(|| {
				for path in env::split_paths(&path) {
					let target = path.join(&cmd);
					let mut cmd_alt = cmd.clone();
					cmd_alt.push(".exe");
					if target.is_file() || // some/path/git
                target.with_extension("exe").exists() || // some/path/git.exe
                target.join(&cmd_alt).exists()
					{
						// some/path/git/git.exe
						return Some(target);
					}
				}
				None
			})
			.clone()
	}

	/*pub fn must_have<S: AsRef<OsStr>>(&mut self, cmd: S) -> PathBuf {
        self.maybe_have(&cmd).unwrap_or_else(|| {
            panic!("\n\ncouldn't find required command: {:?}\n\n", cmd.as_ref());
        })
    }*/
}

// Just use finder for now

/*pub fn check(build: &mut Build) {
    let path = env::var_os("PATH").unwrap_or_default();
    // On Windows, quotes are invalid characters for filename paths, and if
    // one is present as part of the PATH then that can lead to the system
    // being unable to identify the files properly. See
    // https://github.com/rust-lang/rust/issues/34959 for more details.
    if cfg!(windows) && path.to_string_lossy().contains("\"") {
        panic!("PATH contains invalid character '\"'");
    }

    let mut cmd_finder = Finder::new();
    // If we've got a git directory we're gona need git to update
    // submodules and learn about various other aspects.
    if build.rust_info.is_git() {
        cmd_finder.must_have("git");
    }

    // We need cmake, but only if we're actually building LLVM or sanitizers.
    let building_llvm = build.hosts.iter()
        .filter_map(|host| build.config.target_config.get(host))
        .any(|config| config.llvm_config.is_none());
    if building_llvm || build.config.sanitizers {
        cmd_finder.must_have("cmake");
    }

    // Ninja is currently only used for LLVM itself.
    // Some Linux distros rename `ninja` to `ninja-build`.
    // CMake can work with either binary name.
    if building_llvm && build.config.ninja && cmd_finder.maybe_have("ninja-build").is_none() {
        cmd_finder.must_have("ninja");
    }

    build.config.python = build.config.python.take().map(|p| cmd_finder.must_have(p))
        .or_else(|| env::var_os("BOOTSTRAP_PYTHON").map(PathBuf::from)) // set by bootstrap.py
        .or_else(|| cmd_finder.maybe_have("python2.7"))
        .or_else(|| cmd_finder.maybe_have("python2"))
        .or_else(|| Some(cmd_finder.must_have("python")));

    build.config.nodejs = build.config.nodejs.take().map(|p| cmd_finder.must_have(p))
        .or_else(|| cmd_finder.maybe_have("node"))
        .or_else(|| cmd_finder.maybe_have("nodejs"));

    build.config.gdb = build.config.gdb.take().map(|p| cmd_finder.must_have(p))
        .or_else(|| cmd_finder.maybe_have("gdb"));

    // We're gonna build some custom C code here and there, host triples
    // also build some C++ shims for LLVM so we need a C++ compiler.
    for target in &build.targets {
        // On emscripten we don't actually need the C compiler to just
        // build the target artifacts, only for testing. For the sake
        // of easier bot configuration, just skip detection.
        if target.contains("emscripten") {
            continue;
        }

        cmd_finder.must_have(build.cc(*target));
        if let Some(ar) = build.ar(*target) {
            cmd_finder.must_have(ar);
        }
    }

    for host in &build.hosts {
        cmd_finder.must_have(build.cxx(*host).unwrap());

        // The msvc hosts don't use jemalloc, turn it off globally to
        // avoid packaging the dummy liballoc_jemalloc on that platform.
        if host.contains("msvc") {
            build.config.use_jemalloc = false;
        }
    }

    // Externally configured LLVM requires FileCheck to exist
    let filecheck = build.llvm_filecheck(build.build);
    if !filecheck.starts_with(&build.out) && !filecheck.exists() && build.config.codegen_tests {
        panic!("FileCheck executable {:?} does not exist", filecheck);
    }

    for target in &build.targets {
        // Can't compile for iOS unless we're on macOS
        if target.contains("apple-ios") &&
           !build.build.contains("apple-darwin") {
            panic!("the iOS target is only supported on macOS");
        }

        // Make sure musl-root is valid
        if target.contains("musl") && !target.contains("mips") {
            // If this is a native target (host is also musl) and no musl-root is given,
            // fall back to the system toolchain in /usr before giving up
            if build.musl_root(*target).is_none() && build.config.build == *target {
                let target = build.config.target_config.entry(target.clone())
                                 .or_insert(Default::default());
                target.musl_root = Some("/usr".into());
            }
            match build.musl_root(*target) {
                Some(root) => {
                    if fs::metadata(root.join("lib/libc.a")).is_err() {
                        panic!("couldn't find libc.a in musl dir: {}",
                               root.join("lib").display());
                    }
                    if fs::metadata(root.join("lib/libunwind.a")).is_err() {
                        panic!("couldn't find libunwind.a in musl dir: {}",
                               root.join("lib").display());
                    }
                }
                None => {
                    panic!("when targeting MUSL either the rust.musl-root \
                            option or the target.$TARGET.musl-root option must \
                            be specified in config.toml")
                }
            }
        }

        if target.contains("msvc") {
            // There are three builds of cmake on windows: MSVC, MinGW, and
            // Cygwin. The Cygwin build does not have generators for Visual
            // Studio, so detect that here and error.
            let out = output(Command::new("cmake").arg("--help"));
            if !out.contains("Visual Studio") {
                panic!("
cmake does not support Visual Studio generators.

This is likely due to it being an msys/cygwin build of cmake,
rather than the required windows version, built using MinGW
or Visual Studio.

If you are building under msys2 try installing the mingw-w64-x86_64-cmake
package instead of cmake:

$ pacman -R cmake && pacman -S mingw-w64-x86_64-cmake
");
            }
        }
    }

    let run = |cmd: &mut Command| {
        cmd.output().map(|output| {
            String::from_utf8_lossy(&output.stdout)
                   .lines().next().unwrap()
                   .to_string()
        })
    };
    build.lldb_version = run(Command::new("lldb").arg("--version")).ok();
    if build.lldb_version.is_some() {
        build.lldb_python_dir = run(Command::new("lldb").arg("-P")).ok();
    }

    if let Some(ref s) = build.config.ccache {
        cmd_finder.must_have(s);
    }
}*/
